Sensor swap decision delayed

Senior NASA managers delayed a decision today on the possible change-out of critical fuel-depletion sensors on shuttle Discovery's external tank, a move that almost certainly would prompt a launch delay until July.

NASA shuttle program manager Wayne Hale asked engineers to review more data. The tentative plan is for managers and engineers to reconvene Tuesday to take up the matter again.

NASA still is hoping to launch Discovery on the agency's second post-Columbia flight around May 10. A window dictated primarily by daylight launch restrictions will close on May 22.

A decision to swap out the sensors -- which are located inside and near the bottom of the 15-story tank -- likely would force NASA to postpone Discovery's mission until a window that will extend from July 1 through July 19.

NASA officials have said the changeout work could take between three and four weeks.

The tank now is scheduled to be mated to two solid rocket boosters in the Kennedy Space Center Vehicle Assembly Building no earlier than Sunday. A readiness review for the mating operation is scheduled Friday.